• 关键词：SO₂  萱草  保卫细胞  气孔运动  信号调节

• 基金项目：山西省科技基础条件平台项目(No.2014091003-0108);山西省科技攻关项目(No.20110311017-1)

• 魏爱丽
• 太原师范学院生物系, 太原 030031

• 韩二琴
• 西南大学生命科学学院, 重庆 400715

• 张小冰
• 太原师范学院生物系, 太原 030031

• 武凤洁
• 南开大学生命科学学院植物生物学和生态学系, 天津 300071

• 辛晓静
• 南开大学生命科学学院植物生物学和生态学系, 天津 300071

• 王婷
• 太原师范学院生物系, 太原 030031

• 张珊珊
• 太原师范学院生物系, 太原 030031

• 王云山
• 山西省农业科学院园艺研究所, 太原 030031

• 曹冬梅
• 山西省农业科学院园艺研究所, 太原 030031

• 摘要：气孔运动调节对植物抵御环境胁迫具有十分重要的作用,然而,其在SO₂对景观植物毒作用过程中的响应及可能的信号机制目前还不清楚.因此,本文以萱草叶片下表皮为材料,研究了SO₂诱导的萱草保卫细胞气孔运动及其信号调节.结果表明,50~400 μmol·L^-1 SO₂衍生物(Na₂SO₃:NaHSO₃=3:1)处理萱草叶表皮后,保卫细胞气孔开度随处理浓度增大而逐渐减小,Ca²⁺、NO和ROS含量逐渐增加(p<0.05),且处理浓度大于250 μmol·L^-1时,各指标与对照差异极显著(p<0.01);经缓冲液洗脱处理后,50~250 μmol·L^-1 SO₂衍生物处理组气孔开度恢复显著(p<0.01).用250 μmol·L^-1 SO₂衍生物分别与抗氧化剂抗坏血酸(AsA:0.05、0.1、0.5 mmol·L^-1)和过氧化氢酶(CAT:100、200、300 U·mL^-1),Ca²⁺螯合剂EGTA(0.05、0.1、0.5 mmol·L^-1)和Ca²⁺通道抑制剂LaCl₃(0.05、0.1、0.5 mmol·L^-1),以及硝酸还原酶抑制剂NaN₃(0.05、0.1、0.2 mmol·L^-1)、NO清除剂C-PTIO(0.05、0.2、0.5 mmol·L^-1)和 NO 合成酶抑制剂L-NAME(0.01、0.02、0.03 mmol·L^-1)共同作用后,与SO₂衍生物单独处理组相比,气孔关闭程度显著减小,保卫细胞中Ca²⁺、NO 和ROS含量显著降低.用抗氧化剂 AsA、NO干扰剂 L-NAME 和SO₂处理后,ROS、Ca²⁺和NO水平均显著降低,而用钙离子干扰剂EGTA和SO₂处理后,只有Ca²⁺水平显著降低,而ROS、NO水平变化不显著.以上结果表明,NO、ROS和Ca²⁺参与了气孔运动的调节,且Ca²⁺在NO、ROS下游发挥作用.

• Abstract：Stomatal movement regulation plays an important role in resisting environmental stress on plants, but up to now it is unclear about the response of the stomata of landscape plants to SO₂-induced toxicities and the signal transduction mechanism. In this study, epidermal strip experiment was employed to investigate SO₂-induced stomatal movement and its signal regulation in the case of Hemerocallis fulva, with their leaves treated by 50~400 μmol·L^-1 of SO₂ derivatives (Na₂SO₃:NaHSO₃=3:1). The results showed that with the increase of treatment concentrations, the stomatal aperture decreased in size in a dose-dependent manner while the cellular NO,ROS and Ca²⁺ levels increased significantly(p<0.05)(in particular when the concentration of SO₂ derivatives exceeded 250 μmol·L^-1). And within 50~250 μmol·L^-1 of treatment concentrations, the stomatal aperture could be recovered reversibly after the treated leaves were eluted by buffer solution. In addition, SO₂-induced stomatal closure together with increase of cellular NO,ROS,and Ca²⁺ levels could be effectively blocked by adding antioxidant ascorbic acid (AsA:0.05, 0.1, 0.5 mmol·L^-1), hydrogen peroxide enzyme (CAT:100,200,300 U·mL^-1), EGTA (a Ca²⁺ chelator:0.05,0.1,0.5 mmol·L^-1), LaCl₃ (a Ca²⁺ channel inhibitor: 0.05,0.1,0.5 mmol·L^-1), NaN₃ (a nitrate reductase inhibitor:0.05,0.1,0.2 mmol·L^-1), C-PTIO (a NO scavenger: 0.05,0.2,0.5 mmol·L^-1) or L-NAME (a NO synthetase inhibitor: 0.01,0.02,0.03 mmol·L^-1). Addition of L-NAME or AsA in 250 μmol·L^-1 of SO₂ derivatives led to a significant decrease in the levels of cellular NO,ROS and Ca²⁺, whereas addition of EGTA resulted in the decrease of Ca²⁺ levels and posed little influences on NO and ROS levels. The above results suggested that Ca²⁺, NO and ROS were involved in SO₂-induced stomatal closure of leaf guard cells in H. fulva., and Ca²⁺ played significant roles in the downstream of ROS and NO.

• Key words：SO₂  Hemerocallis fulva  guard cell  stomatal movement  signal regulation

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